MapGit is a service to facilitate geotagging your git commits. (Or other commits, but realistically for now it more or less hinges on you using git + github)
You'll install a post-commit hook into your repos. It still requires an opt in flag, so
it's safe to install into your git_template if you don't necessarily want to
tag everything.
From there, at commit time a lon,lat pair is written to a flat file database with the commit hash. This data can be synced to with the mapgit webservice (or a private instance) which then does the appropriate magic to marry this data up with github.
This is all well and good, but you'll still need a mechanism to gather this data. I recommend doko, which is written in python and plays nicely on all platforms (although it's most accurate on OSX with corelocation).
You'll need to fetch a maps api key from google.
Set it to the environment variable GMAPS_API_KEY